Demonstration apparatus



Dec. 11, 1945.

R. J. HEARON DEMONSTRATION APPARATUS Filed Nov. 29, 1943 I QJQ/i 7% Q Q Q 3 Sheets-Sheet l fiairt f earak/ Dec. 11, 1945 R. J. HEARoN 0 DEMONSTRATION APPARATUS Filed Nov. 29, 1945 3 Sheets-Sheet 2 Hill Dec. 11, 1945. HEARQN 2,390,706

DEMONSTRATION APPARATUS Filed Nov. 29, 1943 3 Sheets-Sheet 3 azarzwmz Patented Dec. 11, 1945 UNITED STATES PATENT OFFICE 2,390,706 DEMONSTRATION APPARATUS Robert J. Hearon, Arlington, Va.

Application November 29, 1943, Serial No. 512,231

Claims.

This invention is a demonstration and test apparatus, designed particularly to aid in teaching and illustrating the phenomena of the vacuum tube and the manner in which variations in the electrical characteristics of circuits and elements connected to the electrodes of such tubes affect the operational characteristics of the tubes.

One object of the invention is to provide means in the form of a radio chassis or panel board or similar support upon which may be readily and systematically mounted and interconnected electrically, a vacuum tube or tubes, together with desired conductor bars, or leads, translating or coupling devices and various power connections whereby actual tubes, circuits and networks may be set up in full view of an observer, illustrator, lecturer, designer or experimenter.

Another object of the invention is to provide in an apparatus of the character described quick detachable means for simultaneously mechanically connecting the translating or coupling devices to the chassis or panel board and for electrically connecting these devices in a circuit with the tube electrodes and associated components or circuits.

Another object of the invention is to provide a chassis or panel board having a plurality of conducting jack sleeves or studs mounted therein and having plug or threaded connector receiving terminal portions disposed on opposite faces of the board whereby translating or coupling devices, various power sources and the like may be operatively connected to the jacks on either front or rear faces of. the board, or both, separately or together.

Another object of the invention isto provide in an apparatus or the character described, means for mountinga vacuum tube socket on one face of the chassis or board with the prong receiving terminals thereof electrically connected to a standard circular series of conducting jack sleeves or studs which have exposed terminal portions on opposite faces of the board, together with a receptacle or other quick detachable means for mounting a tube diagram plate or similar representative device on the opposite or viewers side of the panel. The diagram plate carries a pictorial or diagrammatic representation of a tubes internal electrodes arranged with the terminal portions of the illustrated electrodes disposed in juxtaposed relation to the exposed terminals of the jack terminals to which are operatively connected the electrodes of a tube mounted in the tube socket, adjacent to either face of the panel or chassis.

Another object of the invention is to provide in connection with the apparatus described in the previous paragraph, a substantially universal tube socket mounted on one side or face of the panel and a plurality of diagram plates each bearing a distinctive type of tube electrode arrangement, said plates to be selectively mounted,

on the opposite face of the panel, in the manner described, so that for each type of tube used for demonstration purposes a diagram plate showing the actual electrode arrangement of the tube may be mounted on the opposite face of the board.

Another object of the invention is to provide a panel board having plural pairs of spaced jack sleeves or studs and a plurality of translatmg devices, each of the latter beingprovided with spaced attaching and connecting plugs or terminals cooperable with the spaced jacks to physically mount the translating devices upon the panel and electrically connect them with the Jacks.

Another object of the invention is to provide a demonstration device of the character described wherein means are provided for yieldably mounting the jack sleeves or studs upon the panel whereby to insure uniform quick detachable connection between different pairs of jacks and the spaced terminals or plug attaching devices carried by the respective translating devices.

Another object of the invention is to provide preformed contact bars of definite lengths and having means whereby they may be readily associated with the projecting ends of the studs or jack sleeves to connect adjacent sleeves electrically for completing electrical circuits between translating devices mounted in the several jacks.

These and other objects will become apparent from reading the following specification in connection with the accompanying drawings wherein I have described and illustrated preferred forms of my invention. It will be understood,

' however, that such illustration is but for the purpose of example only, and that I reserve the right to make such changes in details of construction and arrangement of parts as fairly fall within the scope of the appended claims without departing from the spirit of my invention.

In the accompanying drawings:

Figure 1 is a front elevation of the panel board.

Fig. 2 is a view similar to Fig. 1 with a typical demonstrating circuit set-up thereon.

Fig. 3 is a rear elevation of the board.

Fig. e is a detailed sectional view of the jack mounting.

Fig. 5 is a perspective view of a diagram plate.

Fig. 6 is a perspective view of another form of diagram plate.

Fig. 7 is a perspective view of a translating device with attached plugs.

Fig. 8 is a fragmental detail view showing the method of securing two panel members together.

Figs. 9 and 10 are diagrammatic views of typical demonstrating circuit set-ups.

Fig. 11 is a fragmentary detail of auxiliary supporting means for the panel.

Fig. 12 is a perspective view showing a modifled form of the panel board.

Fig. 13 is a detailed sectional view showing a modified form of jack terminal.

Fig. 14 is a front elevation of the terminal shown in Fig. 13.

Fig. 15 is a modified form of conductor bar shown in perspective.

Fig. 16 is a fragmentary sectional view of a jack terminal such as shown in Fig. 13, having conductor bars mounted thereon.

Fig. 1'7 is a perspective view of a modified form of conductor bar.

Fig. 18 is a fragmentary plan view of the conductor bar shown in Fig. 1'7.

Referring more particularly to the accompanying drawings, wherein like reference numerals are used to designate like parts throughout, Fig. 1 illustrates the invention as comprising a radio chassis or panel board I together with means for supporting the board in an upright position. I have shown the board provided with a bottom flange member 2 for so supporting the board, and if desirable the fiange may be provided with resilient or cushioning feet or pads 3. Conveniently, the board may be provided with a rearwardly directed flange 4 along the top and side edges thereof to form with the bottom flange a lateral enclosure for the rear face of the panel, but it will be understood from what follows that I can dispense with such lateral flange, if desired, without sacrificing any of the advantages or important objects of the invention as previously set forth.

Furthermore, I haveshown the'fianges 2 and 4 formed integrally with the panel I, but it will be understood, of course, that the panel may be made separate from the flanges and secured thereto in any convenient or desirable manner. I may make the board I and the attached flanges 2 and 4 of metal or any other suitable material. Thus as shown in Fig. 12 I provide a panel board without flanges and mount it upon a suitable supporting frame.

The panel I is provided with a plurality of apertures arranged in predetermined spaced relation and in each such aperture is mounted a conducting jack sleeve 5. As shown in Fig. 4, the apertures 6 provided in the panel board are each fitted with a grommet I of rubber or other suitable resilient insulating material, each such grommet being provided with a peripheral groove 8 designed to receive the edge wall of the aperrespective grommets.

are mounted in respective grommets I by suitable rigid insulating bushing members III, the latter being internally threaded to cooperate with threads 9 of the jack sleeves. The bushings III are threaded on to the jack sleeves from opposite ends and are adjusted into firm engagement with the opposite faces of the grommet whereby to firmly but yieldably mount the jack sleeve in the The yieldability of the jack sleeves in all directions, made possible by the yieldin grommets in which they are mounted, is important in that it permits ready insertion and removal of cooperating attaching plugs carried by the translating device and to compensate for irregularities in spacing of such plug members within reasonable limits. The jack sleeves 5 are arranged in predetermined spaced relation and while I have shown an arrangement wherein the jacks are arranged in several horizontal rows with the jacks of successive rows aligned vertically, any other arrangement may be employed if found desirable.

As previously stated, I propose mounting on one face of the board I, a vacuum tube socket to receive a tube for demonstration purposes. Thus.

in Fig. 3 a tube socket I I is shown mounted on the rear face of the panel I by means of suitable fastener members I2. The members I2 may be in the form of bolts threaded into tapped holes provided in the panel, or the bolt members may extend through un-threaded holes and be provided on their opposite ends with conventional nuts or taps. I prefer to employ a tube socket which is substantially universal in the sense that any of the well known and generally used electron tubes may be mounted therein. Thus, I have shown a conventional octal tube socket and the tube prong receiving contacts I 3 thereof are shown connected respectively to the sleeves of a circumscribing circular series of jacks I4, by conducting wires I5.

Thus, each of the eight tube electrode contacts I3 of the socket II is connected to correspondingly disposed jack sleeves. Centrally of the circular series of jack sleeves I4 I provide an aperture I6 designed to receive an attaching plug I! carried by a diagram plate I 8 shown more clearly in Fig. 5. The plate I8 carries on its front, or exposed face, a pictorial or diagrammatic representation of the electrode arrangement of a given type of tube and when the plate I8 has its plug I'I associated with the aperture I6 as shown in Fig. 2 an observer in front of the board I has before him a clear picture of the actual tube electrodes of the tube mounted in the socket II on the rear face of the board. I prefer to form the plate I8 with peripheral notches I9 corresponding to the terture. The aperatures 6 and the grommet I are met will cause it to assume its natural shape and form when released.

The lack sleeves 5 are threaded externally, preferably from end to end as shown at 9, and

minal portions of the electrodes 20 depicted thereon so that these notches may be arranged in juxtaposition with respect to the exposed portions of the jacks I4 on the front face of the board I. It will be understood, of course, that I propose to provide a plurality of plates such as I8 each carrying the pictorial representation of the electrode arrangement of a particular type of tube and the corresponding number of notches so that these plates may be selectively employed to illustrate the tube electrode arrangement of the particular tube being demonstrated. It is apparent that the student or observer thus has constantly before him a much clearer idea of the tube electrode arrangement than would be possible to get from a casual inspection or long range view of the actual tube.

As previously'suggested, I provide preformed conductor bars by which selected Jack members H may be interconnected electrically to provide actual circuits for a tube mounted in the socket and to include in such circuits, translating devices to be supported upon the panel in the manner previously referred to. Thus, in Fig. 4 I shall show one of the conductor bars as comprising a metal bar 2| having each end thereof provided with an aperture 22. The bars 2| are made of a length between aperture centers to coincide with the spacing between respective jack centers so that the contact bars may be fitted upon adjacent jacks with the exposed portions of the jacks penetrating the apertures 22. The bars 2| may be secured in position upon the Jacks and in electrical contact therewith by suitable nuts 23 threaded upon the jacks and into clamping engagement with the bars. Thus, as shown in Fig. 2, a series of conductorbars 2| are arranged to connect a translating device 25' in circuit with the jacks H which are in turn connected to the electrodes of a tube under demonstration.

Each of the translating devices provided for use in connection with my demonstration panel is, as shown in Fig. 2, preferably provided with an insulating supporting base 26 to which the translating device is firmly secured. The translating device shown in Fig. 7 is a conventional resistor but it will be understood that I propose to similarly mount any desired type of translating device, such as a condenser, a meter, an inductance, a transformer and the like. The terminals of each such translating device are electrically connected to a pair of spaced plug members 21 which are preferably of the split banana type so as to fit snugly Within the smooth bores of the jack members or H. Thus, the translating devices may be quickly mounted upon the panel and electrically connected to any desired pair of jacks and the latter, by the conducting bars 2| previously referred to, connected into a desired circuit or network in an obvious manner.

Electrical power for energizing the circuits and tubes set up on the panel in the manner previousiy described may be supplied from any convenient external source. Preferably, the power connections are made on the rear of the board by flexible conductors carrying plug members at their respective ends similar to the plugs carried by the respective translating devices, so that these plugs may be inserted in any of the jacks 5 or M.

I prefer to include on the face of the panel a diagram plate 28 such as is shown in Fig, 2 carrying on its face a pictorial representation of a source electrical potential, said plate to be associated with the pair of jack sleeves 5 to which a conventional power source is connected on the rear face of the panel as previously suggested. The diagram plate 28 ma be mounted on the panel in the same manner as suggested in respect to the diagram plates l8, or such plate may be provided with end portions having apertures 29 which may interfitted with the exposed terminals of the jack members in insulated relation thereto. In lieu of the full apertures 29, the diagram plates 28 may, if desired, be provided with arcuate no'mhes, such as employed in connection' with the diagram plate I 8 as shown in Figure 5, so that the notched ends of the plates may be firmly crowded between the circular peripheries of the grommet members 1 associated with the jacks which the power source is connected.

The plate from which the diagram plates 18 and 28 are made may be of metal or suitable insulating material, as desired. If of insulation material they may be mounted directly upon the protruding ends of the jack sleeve, but if made of metal, should be suitably insulated with respect to the sleeves so as to avoid short-circuit- 111g.

From the foregoing description it is believed to be obvious that with the required number of contact bars 2| and the proper assortment of translating devices, any desired control circuit may be physically set up on the panel board in clear view of an observer and its relationship with the tube electrodes under test or demonstration clearly illustrated.

It is desirable at times to illustrate and demonstrate the operation of tube circuits involving one or more stages of amplification, or a detector having one or more stages of amplification preceding or succeeding it. This can be readily demonstrated with my apparatus because I provide means for assembling two or more panels, such as shown in Fig. 1, in side by side relationship as suggested in Fig. 8. While any convenient means may be employed for firmly securing adjacent panel boards together with the panels lying in substantially the same vertical plane, I propose to use conventional U-shaped clamping members 3| engaged with the rearwardly directed side flanges 4 of respective panel boards. In order to facilitate connections from the jack sleeves l4 of one panel to the jack sleeves M of a succeeding panel, I arrange the jacks with respect to the side edges of the panels so that this distance is substantially one-half of the distance between jack sleeves of the panel. By this arrangement contact bars of the same length may be employed for joining jacks of adiacent panels as are employed for adjoining jacks of the same panel. In this way any number of stages of amplification may be actually set up and demonstrated, each panel carrying the tube and associated translating dew'ces required in the respective stages of the complete network,

In Figs. 9 and 10 I have shown diagrammatically different circuit arrangements for illustrating different types of circuits. Thus, in Fig. 9 I show a typical demonstrating circuit set-up for illustrating A. C. plate supply, wherein a vacuum tube is diagrammaticall illustrated as including a heater type cathode C energized from a source of alternating current potential a c, and wherein the electrodes PP are energized from a second source of alternated current potential A C. In Fig. 10 I have shown a typical demonstrating circuit set-up for illustrating diode rectification and wherein a heater type cathode c of a vacuum tube is diagrammaticall shown as being energized from an alternating current source of potential a c and wherein the cathode circuit includes a coil 70. The plate electrodes pp are energized from a source of alternating current potential A C. In both of Figures 9 and 10 a translating device such as an ammeter is shown at 25 and the circuit connections between the electrodes and sources of potential are completed by the conductor bars 2|, shown diagrammatically.

The foregoing description of the essential features of my invention relate to but one form of demonstration apparatus. Various modifications thereof may be utilized such as, for instance, the auxiliary supporting means for the panel shown in Fig. 11. The flange 2 of the panel l, as shown in Figs. 1, 2 and 3, adequately supports the panel against rearward tilting, but it may be advisable to provide a forwardly extending foot member 40 secured to said flange 2 in any desired manner.

such as by welding, in order to preclude forward tilting of the panel when-instruments or other translating devices having appreciable weight are mounted on the front face of the panel, I propose providing a forwardly extending foot member 40 at either end of the bottom flange 2, and, as shown, the foot member may have socured to it the rubber pads 3.

In other instances it may be desirable to mount the panel board so as to have a slight rearward inclination in order to preclude forward tilting under the circumstances just related. Thus, I propose to provide a suitable frame member 4| made of wood, plastic, metal or any other suitable material, and fashioned to provide means for receiving and supporting the panel board in an inclined position, as' shown in Fig. 12. When thus constructed, the apparatus forming the subjectmatter of the present invention comprises a Panel board 42 which is devoid of edge flanges such as characterizes the panel board of Figs. 1, 2 and 3. The panel board 42 is secured to the inclined face of the frame member 4| by suitable screws 43. Several of the units comprising the frame member 4| and the panel board 42 may be mounted in horizontal alignment in end to end relation and the jack or terminal members of adjaoent panel boards electrically connected by conductor bars or fiexible leads, as clearly shown in Fig. 12.

I also propose to provide a modified form of jack or terminal for the panel boards for use in circumstances where it is desired to frequently change the connections between jack sleeves and conductor bars. The arrangement previously described, which entails unscrewing the nuts 23 and applying or removing conductor bar 21 and thenv rearranging the nut member, may be used to advantage in instances where a given connection between jacks and conductor bars may be used without change over an appreciable period of time, but where frequent changes are necessary, a quick detachable connection between the conductor bars and jack terminals is desirable. To this end I propose to provide a jack terminal such as shown in Figs. 13, 14 and 15, in whicha jack comprising a solid post 44, is mounted in the panel board by means of a resilient grommet 45, said post or jack carrying intermediate its ends an annular shoulder or flange 4B. The flange 46 abuts one face of.

the grommet 45. and the end of the plug which extends through the grommet is threaded, as shown at 41, to take an interiorly threaded nut or washer 48. The jack terminal is thus firmly but resiliently secured to the panel board. The threaded end 41 of the jack terminal is provided with a longitudinally extending bore 49 for receiving the banana-type plug terminals carried by translating devices such as shown in Fig. 7. The opposite end of the plug 44 extending outwardly of the flange 46 is provided with a sub stantially semi-spherical terminal portion 50, having an axially disposed small bore 5| to receive a pin-type plug or terminal member carried by a translating device. Intermediate the flange 46 and the head 50 of the plug member 44, the latter is provided with a plurality of longitudinally extending diametrically opposed grooves 52, in which are disposed bowed spring members 53 construoted and arranged to extend or project laterally beyond the confines of the generally cylindrical wall of the plug 44. 'Ihespring members 53 may be secured within the respective grooves 52 in any convenient manner, such as by welding one end of each spring member to the post.

To cooperate with the modified form of terminal post just described, I may provide solid metal conductor bars 54 having rectangular apertures 55 in their respective ends, as shown in Fig.

15. The apertures 55 are dimensioned so that transversely they have a dimension corresponding substantially to the diameter of the posts 44, whereas in a longitudinal direction they are dimensioned to appreciably exceed this diameter. Thus, when a bar 54 is mounted upon a post 44, as shown in Fig. 16, the longitudinal side walls 56 of the apertures 55 will snugly engage the post 44 and the bowed springmembers 53 at diametrically opposite points. Thus, two such bars 54 may be superposed upon a given post member, said bars being disposed at right angles to each other, and firm electrical contact may be established between the respective bars and the post 44 through the pairs of spring members 53 along perpendicularly disposed diameters of the post 44. As shown in Eig. 16, the posts 44 are made of a length suchthat a plurality of bars may be superposed thereon to make electrical contact with the posts through the diametrically opposed springs 53. It will be appreciated that the posts 44 may be made of any length desired to tak any desired number of superposed conductor bars, good electrical contact being insured by the right-angular disposition of the bars and the bowed spring members 53.

As an alternative form of conductor bar, having in mind the present scarcity of copper and similar metals of good conducting qualities, I propose to provide a connecting bar of synthetic resin, plastic or similar non-conducting material 51, having metallic strands or wire embedded therein, as shown in Fig. 17. In this form of the invention the connecting bar is provided with a substantially cylindrical aperture 58 at either end of the bar positioned to expose and intersect portions of embedded conductor bars 59 extending longitudinally of the bar 51 from end to end. Thus, as shown in Fig. 18, the portions -60 of the conductor strands 59 exposed within the apertures 58, may contact with the bowed springs 53 of the posts 44 when the latter are inserted within the apertures 58, as the bars 51 are! mounted thereon. It will be understood, of course, that the conductor strands 59 are spaced 3, distance corresponding substantially to the outside diameter of the post 44 so that a good electrical contact is formed when the posts are entered within the holes 58.

It will be understood that the panel board of Figs. 1, 2 and 3, or of Figs. 12, 13 and 14, may

be made of metal, plastic, insulation fiber board .or any other suitable material having the desirable structural characteristics necessary to support the jacks and such instruments and translating devices as are necessary in teaching, demonstration, lecturework and the like.

From the foregoing it is apparent that I have provided a, demonstrating apparatus wherein actual physical circuits may be set up in the clear view of an observer and that said circuits and the manner in which they function may be made clearly apparent even though the tube under actual demonstration is mounted on the rear face of the panel. The resilient or yieldable mounting of the jack members provides for instant attachment and detachment of different types of translating devices and the particular construction of the jack sleeves permits ready connection thereto of power sources and translating devices from either face of the board. The provision of diagram plates for association with the jack members on the front of the board permits the observer to have constantly before him the piece of apparatus or power source which is connected to the board on the rear face thereof and this keeps the face of the board clear of conventional and unimportant items which would tend only to obscure the more important features of the circuit under demonstration.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In apparatus for demonstrating electrical phenomena, a panel board, a vacuum tube socket mounted on one face thereof, a plurality of connecting jacks mounted on said board and arranged in a circular series about said tube socket, said jacks extending through the board and presenting electrical connectibnterminals on opposite faces thereof, there being as many jacks as there are tube prong contacts -on the socket, means electrically connecting the respective tube v prong contacts and said jacks, a diagram plate bearing pictorial representation of the electrodes of the vacuum tube mounted in said socket, and means for removably mounting said plate on the opposite face of the panel and overlying that area of the panel opposed to said socket with the respective electrodes represented thereon disposed in juxtaposed relation to the jack members which are in circuit with the actual electrodes of the tube in said socket,

2. The apparatus for demonstrating electrical phenomena described in claim 1 wherein means are provided for adjustably and detachably mounting the diagram plate on said panel.

3. The apparatus for demonstrating electrical phenomena described in claim 1 wherein plug I and socket means are provided on the diagram plate and panel, respectively, for adjustably and respective jacks to which the corresponding tube electrodes are electrically connected.

5. In apparatus for demonstrating electrical phenomena a panel, a plurality of electrical conducting jacks carried by the panel and extending through the same from one face thereof to the other, an electrical translating device,-support means for said electrical translating device, means electrically connected to said device for mechanically connecting said support means and electrically connecting said translating device removably with pair of jacks on one face of the panel, a diagram plate carrying a pictorial representation of said translating device, and cooperative means carried by the diagram plate and Jacks for mounting said plate on the opposite face of the panel in juxtaposed relation to the jacks to which said translating device is connected.

ROBERT J. HEARON. 

